fix(api): feed push fails if channels is undefined (left blank in UI)

src/server/controllers/guild/api/feed.controller.ts

@@ -39,7 +39,7 @@ export const post = async (request: Request, response: Response) => {
                 url: url,
                 guild_id: guildId,
                 active: active === "on",
-                channels: { create: formattedChannels }
+                channels: channels !== undefined ? { create: formattedChannels } : channels
              }
         });
     }